Which substances have Olympic athletes been caught using?
They wanted to establish which substances teens typically used first.
Numerous reaction catalysts perform their function by providing a reactive surface on which substances can react.
Accordingly, all children with asthma should have skin tests for a battery of common allergens to determine which substances are most likely to set off attacks.
For now, the N.F.L. and its players union decide which substances to test for and how often players may be tested.
There is an inherent uncertainty in determining which substances are safe and which are not, and when their risks outweigh their benefits.
Because the wavelength at which substances absorb radiation depends on their chemical makeup, absorptiometry can also be used for qualitative analysis.
In addition to an awareness of the substances that are of benefit during pregnancy, a knowledge of which substances are harmful and should be avoided is equally important.
He also accounted for biological changes, in which substances appear under new manifestations: as men eat and drink, flesh, bone, and hair grow.
At last, it seems, addiction is being treated as a health rather than a crime issue but as drug-taking supply and demand patterns evolve, so it become ever more difficult to predict which substances will cause the most damage.
Human nutrition, process by which substances in food are transformed into body tissues and provide energy for the full range of physical and mental activities that make up human life.
